1. Technical Field
The present invention relates to a tape drive system using an endless belt circulating partially in contact with, and supplying tension to, the tape.
2. Prior Art
Apparatus of this type is described in U.S. Pat. No. 3,907,230 to which reference may be made to understand the role of the elastic belt and whose disclosure is incorporated by reference herein.
Although this apparatus is satisfactory even in severe operating conditions, it is apparent that the reels of tape have a tendency to form separate groups of coils when they are stored at low temperature.
It has been discovered, by measurements made on prior art apparatus of the tension of the outermost coil of tape on the take-up reel, that this tension, which varies moreover as a function of the filling of the reel, could, in adverse circumstances, disappear, and even give way to a relaxation or slackness of the tape, with in consequence the formation of gaps separating the groups of coils on the wound reel.
The tape tension of the outermost coil of the take-up reel is influenced, according to a function not yet explained, by the friction of the elastic regulating belt, which engages an arc of the periphery of the said reel. The part of the belt directly concerned in the phenomenon is the part of the second loop of the belt disposed downstream from the floating roller/belt/reel contact point to the (or one of the) belt return roller(s) involved with this second loop.
It has been realised in accordance with this invention that the disappearance of tension in the outermost coil of the tape can be considered as due to a loss of local speed of the elastic belt downstream of the floating roller/belt/reel contact point. In other words, in the prior art arrangements where the belt return roller is a free roller, nothing is able to counteract this local loss of speed, even if the overall belt speed remains constant.